Zahra Baker Case: Bone Discovered, Sign of Girl?

Investigators have discovered a bone that "may be related to" the case of missing 10-year-old Zahra Baker, police said today.

Police will send the bone to a medical examiner's office to determine its relation to the case. Its discovery marks the first possible physical remains of the disabled North Carolina girl found since she was reported missing on Oct. 9.

The bone was found after police reportedly searched an area near where the girl's prosthetic leg was uncovered last week.

The find comes a day after the disclosure of jailhouse letters, apparently written by Zahra's stepmother, Elisa Baker, 42, in which she claims police know exactly where the girl is.

The letters maintain neither Elisa Baker nor her husband, Adam Baker, killed the disabled girl, but that Zahra's father did something "horrifying" after the girl was dead.

Police in Hickory, N.C., where Elisa Baker is being held on an obstruction of justice charge, said they had seen images of the letters but couldn't verify that she wrote them without looking at the originals.

Deputy Chief Clyde Deal told ABC News that the handwriting was "similar" to hers and the content matched some of what the woman has been telling police.

"I don't necessarily have any reason to doubt [that Elisa Baker wrote the letters], but I can't say that she did write them either," Deal said.

The letters, obtained by ABC News, appear to shift any blame from Elisa Baker to her husband Adam Baker.

"We really didn't kill her, but what he did after the fact is kinda horrifying," Elisa Baker wrote to crime memorabilia dealer Eric Gein from jail. "[It] makes me scared of him. So I probably am gonna go ahead and file [for divorce]. I have lost my whole life anyway."

Elisa Baker reported her stepdaughter missing on Oct. 9 and was arrested a day later on unrelated charges. She was later charged with felony obstructing justice for allegedly writing a fake $1 million ransom note in relation to her daughter's disappearance.

Gein, who runs the website SerialKillersInk.net, told ABC News he contacted Elisa Baker by letter weeks ago under an assumed name. The letters he received in return, first reported by AOL News, describe strained life in the Baker home. She allegedly signed one letter, "Dark Love Always, Elisa."

Further down the page between doodles of candles and a spider she writes, "Goth's Rule [sic]" and "Vamps Rule!" The comments are similar to those made on a MySpace page believed to belong to Elisa Baker.

Though police have been searching for Zahra's remains for weeks, Elisa Baker claims in the letters, "The cops know where she is and what he has done," apparently referring to her husband.

"[Adam Baker] knows what happened to Zahra, and yet I'm the one in here at least for now," she writes.

In the letters, Elisa Baker now claims Adam Baker actually wrote the phony ransom note.

Elisa Baker Letters Appear to Shift Blame to Husband

A return address on an envelope also obtained by ABC News from Gein features Elisa Baker's name and a P.O. box associated with the Catawba County Sheriff's Department, where she is being held.

Scott Reilly, a court appointed lawyer for Elisa Baker, did not immediately return calls for comment from ABC News.